JP2004194288A - Communication system, transmitting apparatus and transmitting method, receiving apparatus and receiving method, code multiplexing method and multiplex code decoding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the capacity by repeating one frequency using a non-spread cellular scheme. <P>SOLUTION: On the side of a transmitter station, transmission information is divided into a plurality of frames, the frames are encoded, and the power of the encoded signals are amplified in different amplitudes, thereby sending a transmitting signal resulting from collecting the amplified signals and interleaving all the signals. On the side of a receiver station, the transmitted signals are deinterleaved, the signals are successively decoded from the code of a greatest SINR, and the decoded signals are encoded again and successively canceled from the transmitted signal, thereby reproducing the original divided frames. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a communication system, a transmitting apparatus and a transmitting method, a receiving apparatus and a receiving method, a code multiplexing method, and a multiplex code decoding method that operate in a multiple access environment in which a plurality of mobile terminals simultaneously communicate with one base station. In particular, the present invention relates to a communication system, a transmitting apparatus and a transmitting method, a receiving apparatus and a receiving method, a code multiplexing method, and a method of decoding a multiplex code, in which the capacity (communication capacity) is extended by removing interference inside and outside the cell.

  More specifically, the present invention relates to a transmitting apparatus and a communication system that operate at as short a frequency repetition as possible to increase capacity, a transmitting method, a receiving apparatus and a receiving method, a code multiplexing method, and a multiplex code decoding method. The present invention relates to a communication system, a transmitting apparatus and a transmitting method, a receiving apparatus and a receiving method, a code multiplexing method, and a multiplex code decoding method for realizing one-frequency repetition by a non-spreading cellular method to increase capacity.

  Mobile communication originated from the discovery of electromagnetic waves in the first place, and since then research and development has been promoted due to the need for communication with ships, aircraft and trains. In addition, the objects of communication have expanded to vehicles and people. It has become possible to transmit not only telecommunications and telephone data, but also computer data and multimedia contents such as images.

  Recently, miniaturization and cost reduction of mobile terminals are rapidly progressing due to improvements in manufacturing technology and the like. In addition, mobile terminals such as mobile phones are being personalized due to expansion of information communication services and the like. Furthermore, due to the liberalization of communications and the reduction of communications charges, the number of users has been expanding.

  Mobile communication is based on the principle that a mobile station such as an in-vehicle phone or a mobile phone finds the nearest base station and exchanges radio waves between the mobile station and the base station. A communicable range in which radio waves from one base station reach is called a “cell”. The cell is usually a circle of a predetermined radius centered on the base station antenna. Then, by arranging cells without gaps, a communication service area is formed.

  FIG. 19 schematically illustrates a cell configuration in a mobile radio communication system in which a service area is spread over a plurality of base stations as typified by a cellular system. By installing base stations (not shown) at certain fixed intervals and continuously laying out a plurality of cells provided by each base station as shown in FIG. Be built.

  The reason that the mobile communication system uses a cell in this way is to restrict the radio waves of the base station to reach only within the cell, and to repeatedly use the same frequency in other cells, thereby limiting the use of the cell. Effective use of frequency resources and reduction of radio wave output for communication by dividing into cells, miniaturization and power saving of mobile objects usually mounted as battery-powered portable devices, This is because there are merits such as. Recently, due to an increase in the number of cellular phone users (cellular), it has been increasingly required to accommodate as many users as possible in a cell and to make the best use of limited frequency resources. . There are a plurality of mobile terminals in one cell, which communicate simultaneously with one base station. Therefore, from the viewpoint of the base station, it is necessary to multiplex radio signals, that is, multiplex radio signals to detect which signal belongs to which user (multi-user detection).

  2. Description of the Related Art Conventionally, as a multiple access technique in wireless communication, a frequency division multiple access (FDMA) and a time division multiple access (TDMA: Time Division Multiple Access) employed in a second generation PDC (Personal Digital Cellular) have been used. Access), code division multiple access (CDMA) adopted in the third generation, and the like are known.

  TDMA is a communication method in which a communication channel is divided in advance by time slots on a time axis and different time slots are assigned to mobile terminals communicating simultaneously, and is based on a digital method. In the digital cellular phone system in Japan, time division multiplexing of three or six channels is performed.

  In addition, FDMA is a method of performing communication by allocating different frequencies between mobile terminals that communicate simultaneously (that is, for each communication channel). That is, a number of channels used for communication are arranged on the frequency axis, and vacant channels are appropriately allocated and used. FDMA can support both analog and digital communication systems. In Japan, FDMA is adopted for analog type mobile phones and mobile phones.

  CDMA is a scheme in which a wide frequency is shared by a plurality of mobile terminals using spread spectrum. The mobile terminal is assigned a spread spectrum for spread spectrum every time communication is performed, and spreads and transmits a communication signal using the spread sequence. Since the mobile terminal uses a common frequency, all communication signals of other stations cause interference for the own station, and the performance of extracting a received signal from the interference greatly affects the reception level.

  Here, the communication capacity (capacity) is defined as the number of users that can be accommodated per one cell and one channel. In a wireless communication environment in which mobile communication is rapidly and widely spread and a large number of mobile stations exist in the same cell, the biggest issue is how to increase capacity with a small amount of resources.

  In TDMA and FDMA, different frequencies are allocated to adjacent cells, and a plurality of frequencies are repeatedly used. The capacity of these schemes depends only on the number of channels. In CDMA, since the same frequency is used between cells and within a cell at the same time, interference occurs inside and outside the cell. That is, in CDMA, capacity does not depend on the number of channels but on the amount of interference.

  In FDMA and TDMA, the number of users that can be accommodated in one cell is limited to the number of channels obtained by dividing an available frequency band, so that the capacity is small. Further, it is impossible to repeat the same frequency between adjacent cells, and the capacity is small as a whole communication service.

  In CDMA, code division is performed using a spreading sequence composed of orthogonal and pseudo-orthogonal codes. However, since users in a cell share the same frequency, signals of other users are all interference waves. Since the base station can know the spreading sequence used for each mobile terminal, the base station can detect the signal of each user, but conversely, the mobile terminal is used by other mobile terminals. Since the spreading sequence cannot be known, the detection of the user is not realized. Also, it is sufficient that all spreading sequences are orthogonal, but non-orthogonal components become interference components, so that the number of users that can be accommodated with respect to the number of channels created by the pseudo-orthogonal code is small. Further, since CDMA uses a wide frequency band due to spreading, even if one frequency repetition can be realized, the capacity is small.

  In the CDMA system, detection of each signal, that is, multi-user detection can be performed by applying an interference cancellation technology such as an interference canceller IC (Interference Canceller) (for example, see Patent Document 1). This IC demodulates a received signal transmitted from each station on the transmission side, which is composed of the sum of an incoming signal and noise transmitted through each propagation characteristic, in descending order of received power, and cancels its own signal. By repeating the processing, all the received signals can be detected.

  When performing inter-cell multi-user detection by applying an interference elimination technology such as an IC, the receiving station detects all incoming signals from the transmitting-side stations in the cell and out of the cell as desired signals. Therefore, adjacent or neighboring cells can share the same channel in terms of space, time, and frequency. Therefore, a multi-cell configuration using one frequency repetition can be realized using TDMA or FDMA, and the frequency utilization efficiency increases, and at the same utilization efficiency, the capacity (communication capacity) increases.

  However, near the cell boundary, it is expected that the difference between the interference power of the other cell and the reception power of the desired signal will be small, and it is conceivable that both reception signals have the same power. Under such circumstances, there is a problem that decoding and canceling cannot be performed by the IC.

JP-A-2002-84214

  An object of the present invention is to provide an excellent communication system, a transmitting apparatus and a transmitting method, a receiving apparatus and a receiving method, a receiving apparatus and a receiving method, a code multiplexing method, and a multiplexing method, which can remove interference inside and outside a cell and expand capacity (communication capacity). An object of the present invention is to provide a code decoding method.

  A further object of the present invention is to provide an excellent communication system, a transmitting apparatus and a transmitting method, a receiving apparatus and a receiving method, a code multiplexing method, and a method of decoding a multiplex code, which can operate at a frequency repetition as short as possible to increase the capacity. Is to provide.

  A further object of the present invention is to provide an excellent communication system, a transmitting apparatus and a transmitting method, a receiving apparatus and a receiving method, a code multiplexing method, and a multiplex code, which are capable of realizing one-frequency repetition by a non-spreading method and increasing the capacity. Is provided.

The present invention has been made in view of the above problems, and a first aspect of the present invention is a communication system that realizes one-frequency repetition by a non-spreading method to increase capacity,
On the transmitting station side, the transmission information is divided into a plurality of frames, each frame is encoded, each encoded signal is power-amplified with different amplitudes, and the amplified signals are grouped together to perform interleaving over all signals. Send the transmission signal obtained by performing
On the receiving station side, the transmission signal is deinterleaved, sequentially decoded from a code having a large SINR (signal-to-interference and noise power ratio), and the decoded signal is re-encoded and sequentially canceled from the transmission signal. To reproduce the original divided frame,
It is a communication system characterized by the above.

  However, the term “system” as used herein refers to a logical collection of a plurality of devices (or functional modules that realize specific functions), and each device or functional module is in a single housing. It does not matter in particular.

  According to the communication system according to the first aspect of the present invention, the receiving station can separate a desired wave from an undesired wave by utilizing a difference in an interleave pattern. Therefore, multiple access can be realized by using a different interleave pattern for each user. Alternatively, a non-spread multi-cell system with one frequency repetition can be realized by using a different interleave pattern for each cell.

  Therefore, according to the communication system according to the first aspect of the present invention, it is possible to disperse and reduce the power of the interference signal. In the case where the reception power of the desired signal and the reception power of the interference signal, which is a problem in the conventional inter-cell multi-user detection, are equal, decoding becomes possible by applying the present invention. Also, by appropriately designing the amplitude of the power amplifier, the average transmission power can be reduced.

  Here, the transmitting station side may change the amplitude amplification ratio for each frame according to the decoding capability at the receiving station side. Here, the decoding capability on the receiving station side can be determined based on the number of interference signals, noise power, and the number of codewords per frame.

  Further, when the number of code multiplexes increases, the decoding capability improves, but the processing becomes complicated. Therefore, the transmitting station determines the number of code multiplexes according to the decoding capability or processing capability realized at the receiving station.

Further, a second aspect of the present invention is a transmission device or a transmission method for transmitting information in a non-spreading method,
Frame division means or steps for dividing transmission information into a plurality of frames;
Means for encoding each frame, power amplifying means or steps for power amplifying each encoded signal with different amplitude,
Interleaving means or steps for grouping the amplified signals together and interleaving across all signals;
Transmitting means or steps for transmitting a transmission signal obtained by interleaving,
A transmitting device or a transmitting method.

  According to the transmitting apparatus or the transmitting method according to the second aspect of the present invention, the receiving station can separate the desired wave and the interference wave by utilizing the difference in the interleave pattern. By using a different interleave pattern for each cell, a non-spreading multi-cell system with one frequency repetition can be realized. Also, multiple access can be realized by using different interleave patterns for each user.

  The power amplifying means or step may change the amplitude amplification ratio for each frame in accordance with the decoding capability on the receiving station side. Here, the decoding capability on the receiving station side can be determined based on the number of interference signals, noise power, and the number of codewords per frame.

  Further, the frame division means or step may determine the number of code multiplexes according to the decoding capability or processing capability realized on the receiving station side.

  In the transmitting apparatus or the transmitting method according to the second aspect of the present invention, the ratio of the amplitude amplification for each frame is changed according to the decoding capability on the receiving station side. For example, the number of interference signals and noise power, The amplitude value is calculated based on the number of codes having different amplitude values. Here, since the reception power of the interference signal varies, the interference power is set to be the worst value, and the amplitude value of the code is calculated assuming that the power of the interference wave is equal to that of the desired wave. ing.

  However, in an actual propagation path, the power of a plurality of interference waves is rarely equal to that of a desired wave, and there is a problem that transmission power is lost in most situations. In addition, since the cell arrangement status and the traffic that varies in location and time are not taken into account, if the code is designed in accordance with a severe situation, transmission power loss occurs in a favorable situation.

  Therefore, the transmission device or the transmission method according to the second aspect of the present invention further includes a propagation path condition monitoring means or step for monitoring a state of traffic or the like at certain intervals, and the power amplifying means or step includes: The number of interference signals to be considered or the number of codewords in one frame may be changed according to the situation, and the amplitude value of each code may be updated as needed. Further, a margin may be given to the amplitude value in order to more finely control the amplitude value. However, when the number of codewords in one frame is changed, it is necessary to notify the receiver of the number of codewords. On the other hand, when only the number of interference signals to be considered and the margin of the amplitude value are changed, it is not necessary to notify the receiver of information.

  Here, the received signal is roughly classified into two types, a desired signal and an interference signal to be considered, and an interference signal not to be considered, according to the magnitude of the received power. The “interference signal to be considered” here is a major interference signal of a large received signal that greatly affects a desired signal.

  By limiting the number of interference signals to be considered, the interval of the amplitude ratio is narrowed, and as a result, the transmission power can be suppressed lower. However, in this case, there are actually many other interference waves. Here, the power sum of the interference waves not considered as these interference waves will be referred to as “residual interference power”. The residual interference power causes an increase in noise when viewed from the receiver, and causes deterioration of decoding characteristics.

  On the other hand, when the number of interference signals to be considered increases, the average transmission energy increases, and when the number of codewords in one frame increases, the average transmission energy decreases. However, if the number of codewords is increased, the number of bits per code is reduced, so that the decoding capability is reduced when turbo codes are used.

  In the power amplifying means or the step, the residual interference power (consisting of the power sum of the interference waves not considered as the interference wave) may be considered when calculating the amplitude value of each code. For example, the base station collects information on the average residual interference power from each terminal, and calculates the amplitude value of each code in consideration of the value. If the average residual interference power is large, the low-level code may be buried in the residual interference and cannot be decoded, so the amplitude of the low-level code is increased. In this case, the amplitude of the high-level code increases, but in order to maintain the average transmission power, the number of interference waves to be considered, the number of codes in one frame, the margin of the amplitude value, and the like are adjusted.

A third aspect of the present invention is to encode each frame obtained by dividing transmission information, power-amplify the encoded signals with different amplitudes, and collectively amplify the amplified signals to obtain all signals. A receiving device or a receiving method for receiving a transmission signal obtained by performing interleaving over,
Deinterleaving means or steps for deinterleaving the transmission signal;
Decoding means or steps for sequentially decoding from a code having a large SINR;
Signal canceling means or step of re-encoding the decoded signal and sequentially canceling from the transmission signal;
A receiving device or a receiving method.

  According to the receiving apparatus or the receiving method according to the third aspect of the present invention, it is possible to separate a desired wave and an interference wave by deinterleaving using a difference in an interleaving pattern used on a transmitting station side. it can. By using a different interleave pattern for each cell, a non-spreading multi-cell system with one frequency repetition can be realized. Also, multiple access can be realized by using different interleave patterns for each user.

  Note that signal diffusion processing may be added in addition to this method. However, the spreading here is for reducing the power of the interference signal, and is not focused on user identification or separation as in the CDMA system.

  As described in detail above, according to the present invention, an excellent communication system, a transmitting apparatus and a transmitting method, a receiving apparatus and a receiving method, capable of realizing one frequency repetition by a non-spreading method and increasing the capacity. It is possible to provide a code multiplexing method and a multiplex code decoding method. The present invention is essentially different from the so-called CDMA system because user detection is performed by a non-spreading system.

  According to the present invention, it is possible to disperse and reduce the power of an interference signal. In the case where the reception power of the desired signal and the reception power of the interference signal, which is a problem in the conventional inter-cell multi-user detection, are equal, decoding becomes possible by applying the present invention. Also, by appropriately designing the amplitude of the power amplifier, the average transmission power can be reduced.

  Further, according to the present invention, by making the bride's mouth of a transmission signal variable according to the propagation environment of the system, it is possible to improve decoding characteristics while maintaining the average energy of transmission symbols.

  Further, according to the present invention, the amplitude value of each code can be freely set by making the number of codes giving different amplitude values and the number of interference signals to be considered variable.

  Further, according to the present invention, an optimal system design can be realized by making the amplitude value of the transmission code variable according to the cell arrangement and the congested time zone or location. Further, by providing a margin for the designed amplitude value of each code, it is possible to design a code with a higher degree of freedom.

  In addition, according to the present invention, the receiver is designed to design the amplitude value of each code by changing only the number of interference signals to be considered and the margin of the amplitude value without changing the number of codes giving different amplitude values. The decoding process can be performed without obtaining specific information.

  Further, according to the present invention, by examining the interference power of the entire system in advance, it becomes possible to determine the optimal parameter for determining the amplitude value of each code, and the decoding characteristics are improved.

  Further objects, features, and advantages of the present invention will become apparent from more detailed descriptions based on embodiments of the present invention described below and the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

A. First embodiment
A-1. Transmission / Reception System Here, among multi-cell wireless systems such as cellular, a non-spreading method that does not use a spreading sequence for multiple access (that is, does not perform CDMA) is considered. That is, TDMA or FDMA is used for multiple access, and signals of users in a cell are arranged orthogonally.

  Further, an OFDM (Orthogonal Frequency Division Multiplexing) scheme is adopted as a modulation scheme. OFDM is a type of multi-carrier (multi-carrier) transmission system, and the frequency of each carrier is set such that the carriers are orthogonal to each other within a symbol section. Further, by inserting a guard interval, it is possible to remove the influence of a delayed wave and interference from other users in the cell. Therefore, no intra-cell interference occurs.

  In the wireless communication system described below, one frequency repetition is assumed. That is, since the same frequency is used in adjacent cells, there is interference between cells. The present invention is a technique for removing the inter-cell interference and correctly decoding a desired signal.

  FIG. 1 schematically shows a transmission model according to an embodiment of the present invention. In the example shown in the figure, it is assumed that a certain transmitting station (user A) multiplexes and transmits two codes and receives interference from another station (user B) on a propagation path. In the illustrated example, the signal power ratio is 4: 1.

In the transmitter of user A, the transmission information is converted from serial to parallel, divided into I _AX (101) and I _AY (102), and encoded using encoders X (103) and Y (104), respectively. Become The configuration of the encoder X (103) and the encoder Y (104) may be the same.

  The encoded signal is amplified by power amplifiers (105) and (106) having different amplitudes from each other. In the present embodiment, the power amplifiers (105) and (106) are amplitude amplifiers for digital signal processing, and are not power amplifiers.

  The amplified signals AX and AY are merged by parallel-serial conversion, and are random interleaved (mixed) by the interleaver A (107) over two code sections. The interleaved signal TxA becomes the transmission signal.

On the other hand, in the case of user B existing in a cell different from user A, similarly, the transmission information is subjected to serial-parallel conversion, divided into I _BX (111) and I _BY (112), The signal is encoded by the encoder Y (114), further power-amplified by the power amplifiers (115) and (116) having different amplitudes, and the amplified signals BX and BY are merged and randomized by the interleaver (117). By performing interleaving, a transmission signal TxB is obtained.

  Note that the encoder X (113) and the encoder Y (114) may be the same as the user A. The amplitude patterns of the power amplifiers (115) and (116) are arbitrary, but may be the same as or different from the user A. In this specification, for simplicity, the amplitude patterns are equal for each user, 4 and 1.

  However, the interleave pattern is unique at least in a neighboring cell that receives interference. In the example shown in the drawing, it is assumed that interleaver A (107) and interleaver B (117) have different interleave patterns.

  By using a different interleave pattern for each cell, a non-spreading multi-cell system with one frequency repetition can be realized. Also, multiple access can be realized by using different interleave patterns for each user.

  In the communication path, the transmission signals TxA and TxB from each of the users A and B are added up to become the interference signal AX + AY + BX + BY (120).

  FIG. 2 schematically shows a configuration of a reception model corresponding to the transmitter configuration shown in FIG. As described below, this receiver can receive signals that have been interfered on a communication channel, and can separate and detect each signal. However, in the drawing, the noise term is not included in the signal component.

  The transmission signals from user A and user B are combined and arrive at the receiver. The received signal (120) is AX + AY + BX + BY (see FIG. 1).

  First, the received signal (201) is deinterleaved using the deinterleaver A (201) of the user A. In the present embodiment, the interleave pattern is unique at least in the neighboring cells that suffer interference. Here, there is no correlation in the interleave pattern between user A and user B (described above). Therefore, the output of the deinterleaver A (201) is AX + (BX + BY) / 2, and the interference component is reduced by half.

Next, the output signal of the deinterleaver A (201) is supplied to the decoder X (202) and decoded. The decoder X (202) decodes only the code X having the highest SINR (that is, the most likely code). If the reception power of the desired signal AX is sufficiently larger than the power (BX + BY) / 2 of the interference signal, the AX can be decoded without error and the decoded signal _AX can be obtained.

  Here, assuming that the signals from the user A and the user B are received with equal power, the power ratio between the desired signal AX and the interference signal (BX + BY) / 2 is 4: 2.5, that is, 1.6 times (2. 0 dB). Therefore, error-free decoding can be realized by using, as an original code, a turbo code or the like having a required CIR (Carrier to Interference power Ratio: signal power to interference power ratio) of 2.0 dB or less.

  Further, the received signal (201) is deinterleaved using the deinterleaver B (211) of the user B. Since there is no correlation in the interleave pattern between user A and user B, the output of deinterleaver B (211) is BX + (AX + AY) / 2, and the interference component is reduced by half.

Next, the output signal of the deinterleaver B (211) is supplied to the decoder X (212) and decoded. The decoder X (212) decodes the signal X having a large SINR. Since the reception power of the desired signal BX is sufficiently larger than the power (AX + AY) / 2 of the interference signal, it is possible to obtain the signal _IBX decoded without error.

Next, the components of the decoded signals I _AX and I _BX are canceled from the received signal.

After the signal I _AX decoded by the decoder X (202) is re-encoded by the encoder X (203), it is amplified using the power amplifier (204). The interleaver A (205) receives the decoded signal AX and the signal of all 0 as the other signal AY to be merged, and performs interleaving. Interleaver A (205) has the same configuration and uses the same interleave pattern as interleaver A (107) on the transmitter side. As a result of the interleaving, a replica of the transmission signal of the user A having only the signal component of AX is generated. Therefore, the signal component AX is canceled from the reception signal (120) using the differentiator (216), and the output signal AY + BX + BY is obtained. . When there is a change such as fading in the propagation path, the replica of the propagation path change is multiplied.

Similarly, after the signal I _BX decoded by the decoder X (212) is re-encoded by the encoder X (213), it is amplified by using the power amplifier (214). The interleaver B (215) receives the decoded signal BX and the signal of all 0 as the other signal BY to be merged, and performs interleaving. Interleaver B (215) has the same configuration and uses the same interleave pattern as interleaver B (117) on the transmitter side. As a result of the interleaving, a replica of the transmission signal of the user B having only the BX signal component is generated. Therefore, the signal component AX is canceled from the reception signal (120) using the differentiator (206), and the output signal AX + AY + BY is obtained. .

  Finally, the second power level signals AY and BY from each transmitter are decoded. First, the output signal (AX + AY + BY) of the differentiator (206) is deinterleaved using the deinterleaver A (207) again. Deinterleaver A (207) has the same configuration and uses the same interleave pattern as deinterleaver A (201).

The outputs of the deinterleaver A (207) are AX + BY / 2 and AY + BY / 2, and the power of the interference signal BY is reduced by half. Next, the decoder Y (208) decodes the signal AY + BY / 2 with respect to Y which is a code having a large SINR. Here, if the difference between the desired signal AY and the interference power BY / 2 is sufficiently large, AY can be decoded by the decoder Y (208) without error, and the decoded signal I _AY can be obtained.

  Similarly, the output signal (AY + BX + BY) of the differentiator (216) is deinterleaved using the deinterleaver B (217) again. The deinterleaver B (217) has the same configuration and the same interleave pattern as the deinterleaver B (211).

The outputs of the deinterleaver B (217) are BX + AY / 2 and BY + AY / 2, and the power of the interference signal AY is reduced by half. Next, the decoder Y (218) decodes the signal BY + AY / 2 with respect to Y which is a code having a large SINR. Here, if the difference between the desired signal BY and the interference power AY / 2 is sufficiently large, BY can be decoded without error by the decoder Y (218), and the decoded signal I _BY can be obtained.

According to the above procedure, all the signals I _AX , I _AY , I _BX , and I _BY transmitted from the user A and the user B are decoded.

  In the above-described embodiment, the received signals of all users are input to the first-stage deinterleaver A (201) and deinterleaver B (211), and the signals are decoded and canceled in cascade from the signal having the large SINR. However, the gist of the present invention is not limited to this. For example, iterative decoding can be applied to increase the decoding accuracy. Hereinafter, the procedure of iterative decoding will be described.

  First, after decoding AX, a signal AY + BX + BY in which AX is canceled is obtained from the received signal AX + AY + BX + BY by the differentiator (216).

  Next, BX + AY / 2 is obtained by inputting the signal from which the AX has been canceled to the deinterleaver B (211) for the user B. Since AX, which is an interference component, has already been canceled in this signal, BX decoding accuracy is improved.

  Similarly, after decoding BX, a signal AX + AY + BY in which BX is canceled is obtained from the received signal AX + AY + BX + BY by a differentiator, and this signal is input to a deinterleaver A (201) for user A to obtain AY + BY / 2. Can be Since BX, which is an interference component, has already been canceled in this signal, the decoding accuracy of AX is improved.

  In this way, it is possible to repeatedly perform decoding by giving mutual decoding results as input of the other party between users.

Iterative decoding can also be applied between codes in different stages (amplified by power amplifiers having different amplitudes). In the example shown in FIG. 2, AX is decoded first, then AY is decoded, and the decoding process ends. By re-encoding the decoded signal I _AY , canceling the re-encoded AX and AY from the received signal (120), and inputting it to the first stage deinterleaver (211) of the user B, the BX And BY can be decoded.

A-2. Method of Setting Amplitude Value of Power Amplifier A code multiplexing method in inter-cell multi-user detection (IC-MUD: Inter-Cell Multi-User Detection) described with reference to FIGS. 1 and 2 is referred to as UCM (Unbalance Code Mixing). ). IC-MUD is a technique for implementing one-frequency repetition by detecting, decoding, and removing interference from other cells in an FDMA or TDMA intra-cell orthogonal system. UCM is a code multiplexing and interference elimination method for decoding a plurality of signals received at equal power together.

  FIG. 3 schematically shows the configuration of a UCM transmitter. In the figure, M is the number of users (the number of interference signals), and N is the number of codes to be multiplexed by UCM (the number of codewords in one frame). Here, since the inside of the cell is orthogonal and does not cause interference, it is assumed that all users are in different cells for simplicity of explanation.

  The transmission data is subjected to serial-parallel conversion and encoded by an encoder. The encoded transmission data is multiplied by an amplitude determined for each codeword by a power amplifier, and then time-multiplexed by a multiplexer MUX.

The power amplifier multiplies the k-th code word by an amplitude value √a ^(k) (where 0 <k <N−1). The amplitude value calculation unit calculates an amplitude value based on the number of interference signals, the number of codewords in one frame, and noise power.

Interleaved over N code followed by interleaver L _m, for example after the QPSK modulation, the OFDM-modulated transmission signal with pilot symbols. FIG. 3 shows an example in which QPSK (Quadrature Phase Shift Keying) is used as a modulation method. The interleaving uses random interleaving having a different pattern for each cell. The pilot symbol is an orthogonal code unique to each cell.

  In the present embodiment, the amplitude value is calculated based on the number of interference signals, the number of codewords in one frame, and noise power (described above). In the above description, the power ratio of the power amplifier is 4: 1. Hereinafter, a specific method of designing the power ratio, that is, the amplitude value of each code will be described.

The amplitude value of each code from which all signals can be decoded is obtained. The transmitter prepares a N code of required SNR i.e. _{E rs / (n 0/2} ) = ρ. Here, E _rs is the signal energy per real number, and n ₀ is the power spectral density on both sides of the noise. The energy per real number of the k-th code C ^(k) is set to E _rs ^(k) (E _rs ^(k) > E _rs ^(m) , k> m), and then interleaved over N codes. To send. At the receiving end, it is assumed that the signals of M users are received at the same level.

In addition, since the inside of a cell is orthogonal, it is assumed that interference comes from another cell. Moreover, the variance of the noise to be added per real number and ^{_{n 0/2 = σ n 2}} . At this time, assuming that the codes from C ^(N-1) to C ^{(k + 1) of} all the transmitters have been decoded and cancelled, the condition for decoding C ^(k) is expressed by the following equation. You.

  Figure 4 shows the decoding process. It is assumed that the number of multiplexed codes of each user is N = 4 and the number of users having equal reception power is M = 3. In the illustrated example, it is assumed that there is no interference signal having other received power.

The left side of FIG. 4 shows the energy per symbol of each user when a certain desired wave is deinterleaved. Since the undesired wave has a random interleaving pattern different from that of the desired wave, the energy of one interference signal added to the desired signal after deinterleaving is the average of the energy of the codes of all levels. Since there are M-1 undesired signals, the energy obtained by multiplying this energy by M-1 is all interference energy, and the energy of E _rs ^(k) is determined by the above equation.

When all the codes have been received by the decoder satisfying energy, code C ⁽³⁾ of all the users with the energy of E _rs ⁽³⁾ is decoded. At this time, the energy of each code when the codes C ⁽³⁾ of all users are cancelled is as shown in the right side of FIG.

Here, the hatched portion indicates the energy of the canceled signal. Since the code C ^{(3) of} the interference signal is also canceled, it can be seen that the energy of the interference signal is also reduced. Therefore, the code C ⁽²⁾ having the energy of E _rs ⁽²⁾ can be decoded next, and thus the code having the larger SINR is sequentially decoded.

The minimum E _rs ^{(k) at which} all codes can be decoded is obtained by solving the recurrence equation using the above equation (1) as an equal sign, and is expressed by the following equation. The amplitude value a ^(k) by which the k-th codeword is multiplied is proportional to E _rs ^(k) .

Consider the worst case where the number of users is M = 2 and the received powers of both are equal (because the interference signal is easy to decode when the reception power of the interference signal is large). In this case, it indicates the minimum decodable average E _rs / (n _0/2) with respect to the required E of original codes _rs / (n _0/2) in FIG. As code multiplexing number N is larger average _{E rs / (n 0/2} ) is smaller, the value N = 16 is substantially converged.

Also shows the average _{E rs / (n 0/2} ) when the number of users and M = 3 in FIG. 6. Here, too, the case where the reception powers of all users are equal is considered. Larger average than when the number of users _{M = 2 E rs / (n} 0/2) are required.

A-3. The scope This section decodable reception power in accordance with the transmission signal design method described above, will be explained the range of the received power each code can be decoded.

The number of users M = 2, the required E of original codes _{rs / (n 0/2)} = ρ a 1.0 ₍₀ [dB]), and n 0 /2=1.0 (0 [dB] ). At this time, the range of the receivable reception power when the negative number N = 1, 2, 4, 8 is shown in FIGS. However, in each figure, the vertical axis represents the average of the desired user _{E rs / (n 0/2} ) [dB], the average horizontal axis of the interference user _{E rs / (n 0/2} ) [dB]. When the number of codes N is used as a parameter, the range of the power ratio that could not be decoded is plotted. The difference in the pattern of the plot indicates N symbols.

  When N = 1, that is, when the present invention is not used, as shown in FIG. 7, when the difference in reception power between the desired user and the interference user is small, decoding is impossible even when the reception power of the desired signal is sufficiently large. It becomes. However, by using a plurality of codes N and applying the present invention, it can be understood from FIGS. 8 to 10 that decoding can be performed if the received power is sufficiently large even when the powers of both are equal. That is, by increasing the number of code multiplexes, the receivable area increases, and the decoding capability improves.

A-4. Example of Bit Error Rate Characteristics The results of computer simulation performed using the amplitude value of the power amplifier designed according to the above design method will be described below. Here, the following assumptions are used.

1. The propagation path is AWGN channel 2. The received SINR of each code is known.
3. The reception timing of each user is the same.
4. The received power of each user is equal (ie, the worst situation for multi-user detection)

  In addition, a turbo code using a permutator of 3GPP (3rd Generation Partnership Project) is used as the original code. The number of information bits per code was 3456 bits, the coding rate R = 1/2, and the number of repetitions was 20 times.

FIG. 11 shows average bit error rate characteristics when the number of equal power users M = 2, that is, when the number of interfering users is one. The horizontal axis in the average of the desired signal _{E rs / (n 0/2} ), the vertical axis represents the average bit error rate of all users, the total code. Note that the number of simulation bits is 10 M bits per user per code. In this simulation, the information of the interference signal is considered in the decoding process of the turbo code, and the likelihood is calculated using the likelihood information of the code decoded in the preceding stage.

For comparison, the bit error rate characteristics of the original code are shown ((M, N) = (1, 1) in the figure). When the required _{E rs / (n 0/2} ) (= ρ) the bit error rate is the smaller value than ^10-6, the From this figure [rho = 1.2 dB. The energy per symbol of each code was calculated from the above equation (2) using this value.

As the code multiplexing number N increases, it is possible to make the energy interval of each code closer. Therefore, the average _{E rs / (n 0/2} ) required to transmit without error is small. The broken line in the figure is the average designed _{E rs / (n 0/2} ). The reason why the simulation value is better than the calculated value is that the accuracy of decoding is improved by using the likelihood information of the preceding stage when decoding the turbo code.

B. Second Embodiment In the first embodiment described above, the ratio of the amplitude amplification for each frame is changed according to the decoding capability on the receiving station side. For example, the number of interference signals and noise power, different amplitudes, The amplitude value is calculated by the number of codes having a value. Here, since the reception power of the interference signal varies, the interference power is set to be the worst value, and the amplitude value of the code is calculated assuming that the power of the interference wave is equal to that of the desired wave. ing.

  However, in an actual propagation path, the power of a plurality of interference waves is rarely equal to that of a desired wave, and there is a problem that transmission power is lost in most situations. In addition, since the cell arrangement status and the traffic that varies in location and time are not taken into account, if the code is designed in accordance with a severe situation, transmission power loss occurs in a favorable situation.

  In an actual cellular system, the cell arrangement method is not uniform, and the traffic congestion status differs depending on the place and time zone. Therefore, in the second embodiment of the present invention, the situation of traffic and the like is monitored at certain intervals, and the number of main interference signals and the number of codewords in one frame are changed according to the situation. ) Is calculated to update the amplitude value of each code.

  However, when the number of codewords in one frame is changed, it is necessary to notify the receiver of the number of codewords. On the other hand, when only the number of interference signals to be considered and the margin of the amplitude value are changed, there is no particular need to notify the receiver of information (adjustment of the margin of the amplitude value will be described later).

  FIG. 12 schematically shows the configuration of a UCM transmitter according to the second embodiment of the present invention. In the figure, M is the number of users (the number of interference signals), and N is the number of codes to be multiplexed by UCM (the number of codewords in one frame). Since the cells are orthogonal to each other and do not cause interference, it is assumed that all users exist in different cells for the sake of simplicity.

  The transmission data is subjected to serial-parallel conversion and encoded by an encoder. The encoded transmission data is multiplied by an amplitude determined for each codeword by a power amplifier, and then time-multiplexed by a multiplexer MUX.

The power amplifier multiplies the k-th code word by an amplitude value √a ^(k) (where 0 <k <N−1). The amplitude value calculation unit calculates the amplitude value based on the number of interference signals to be considered, the number of codewords in one frame, and noise power.

Interleaved over N code followed by interleaver L _m, for example after the QPSK modulation, the OFDM-modulated transmission signal with pilot symbols. FIG. 12 shows an example in which QPSK (Quadrature Phase Shift Keying) is used as the modulation method. The interleaving uses random interleaving having a different pattern for each cell. The pilot symbol is an orthogonal code unique to each cell.

  In the present embodiment, the amplitude value is calculated based on the number of interference signals to be considered, the number of codewords in one frame, and noise power. Here, the received signal is roughly classified into two types, a desired signal and an interference signal to be considered, and an interference signal not to be considered, according to the magnitude of the received power. The “interference signal to be considered” here is a major interference signal of a large received signal that greatly affects a desired signal.

  FIG. 13 shows the received desired signal and all the interference signals in order of the magnitude of the power. At the time of calculating the amplitude value, only an interference signal exceeding a predetermined threshold is treated as an interference signal to be considered. By limiting the number of interference signals to be considered in this way, the interval of the amplitude ratio is narrowed, and as a result, the transmission power can be suppressed lower. However, in this case, there are actually many other interference waves. Here, the power sum of the interference waves not considered as these interference waves will be referred to as “residual interference power”. The residual interference power causes an increase in noise when viewed from the receiver, and causes deterioration of decoding characteristics.

  On the other hand, when the number of interference signals to be considered increases, the average transmission energy increases. When the number of codewords in one frame is increased, the average transmission energy is reduced. However, if the number of codewords is increased, the number of bits per code is reduced, so that the decoding capability is reduced when turbo codes are used.

  In order to control the amplitude value more finely, a margin may be given to the amplitude value. FIG. 14 shows a modification of the transmitter shown in FIG. In the configuration shown in FIG. 12, the amplitude value calculation unit calculates the amplitude value based on the number of interference signals to be considered, the number of codewords in one frame, and noise power. On the other hand, in the example shown in FIG. 14, the amplitude value calculation unit performs the calculation by further giving a margin to the amplitude value.

  A method of updating the amplitude value when the decoding characteristic is degraded due to an increase in the number of interference signals will be described below with reference to the flowchart shown in FIG.

  First, the state of the propagation path is investigated (the propagation path is always estimated at the time of decoding) (step S1), and the number of interference signals to be considered is determined (step S2).

  Here, when the number of interference signals increases (step S3), the average energy increases, so that the number of codewords per frame is increased to suppress the increase (step S4). However, when the number of codewords in one frame is changed, the number of codewords is notified to the receiver side (step S5) (same as above).

  If the number of codewords is too large, the characteristics of the turbo code deteriorate (step S6). Therefore, the margin of the amplitude value is reduced (the difference between the amplitude values between codewords is reduced) (step S7), and the average energy is increased. Not to be.

  On the other hand, when the number of interference signals decreases (step S8), the number of codes in one frame is reduced (steps S9 and S10), and the amplitude value is updated by increasing the amplitude value margin (step S11). .

  FIG. 16 schematically illustrates the configuration of a UCM receiver according to the present embodiment. The receiver shown in the figure can receive and process the transmission signals from the transmitters shown in FIGS. 12 and 14, and also corresponds to the transmitter according to the first embodiment shown in FIG. Hereinafter, the configuration and operation of the receiver will be described.

  The received signal from each cell is subjected to phase compensation in a channel estimation / compensation unit based on channel fluctuations estimated from the respective pilot symbols.

  Thereafter, the signal is deinterleaved through OFDM demodulation and QPSK demodulation. When the deinterleaving of the received signals of all users is completed, the code detection unit selects the codeword having the highest SINR and decodes the code.

  The decoded data is encoded in the re-encoding unit shown in the lower part of the figure, and is again UCM-multiplexed. Here, symbols that are not currently decoded are multiplexed as 0. Also in the OFDM modulation, the pilot symbol is treated as 0, and after taking into account the estimated channel fluctuation, the canceller cancels the received signal from the received signal. In this way, decoding and cancellation are repeated until all necessary codewords can be decoded.

  If the decoding characteristic changes significantly due to a change in traffic or an increase or decrease in the number of interfering stations, the receiver notifies the transmitter of the information. The transmitter recalculates the amplitude value of the code based on the notification from the receiver, and multiplexes the code using the new amplitude value. Alternatively, the transmitter may estimate the channel state of the link to be transmitted from the channel state received by itself, and recalculate the amplitude value. In the latter case, a special procedure for notifying the propagation path condition from the receiver to the transmitter becomes unnecessary.

  If the transmitter changes the number of codewords per frame and resets the amplitude value of each codeword, the frame configuration changes, so that the information needs to be transmitted to the receiver. On the other hand, when the number of codewords is fixed and the amplitude value of each code is reset according to the number of interference signals to be considered and the margin of the amplitude value, it is not necessary to notify the receiver of that.

C. Third Embodiment In a second embodiment of the present invention, a received signal is roughly classified into a desired signal and an interference signal to be considered and an interference signal not to be considered according to the magnitude of the received power. I have. That is, a major interference signal having a large received signal that greatly affects a desired signal is treated as an "interference signal to be considered", and the amplitude value of each code is calculated based on the number of interference signals to be considered.

  By limiting the number of interference signals to be considered in this way, the interval of the amplitude ratio is narrowed, and as a result, the transmission power can be suppressed lower. On the other hand, there are actually many other interference waves. The “residual interference power”, which is the sum of the powers of the interference waves not considered as these interference waves, causes an increase in noise when viewed from the receiver, and causes deterioration of decoding characteristics.

  Therefore, in the third embodiment of the present invention, the amplitude value of each code is determined in consideration of the interference power of the entire system including the residual interference power when calculating the amplitude value of each code. FIG. 17 schematically shows the configuration of a UCM transmitter according to the third embodiment of the present invention. In the figure, M is the number of users (the number of interference signals), and N is the number of codes to be multiplexed by UCM (the number of codewords in one frame). Since the cells are orthogonal to each other and do not cause interference, it is assumed that all users exist in different cells for the sake of simplicity. Hereinafter, the configuration and operation of the transmitter shown in FIG.

  The transmission data is subjected to serial-parallel conversion and encoded by an encoder. The encoded transmission data is multiplied by an amplitude determined for each codeword by a power amplifier, and then time-multiplexed by a multiplexer MUX.

The power amplifier multiplies the k-th code word by an amplitude value √a ^(k) (where 0 <k <N−1). The amplitude value calculation unit calculates the amplitude value based on the number of interference signals to be considered, the number of codewords in one frame, and noise power.

Interleaved over N code followed by interleaver L _m, for example after the QPSK modulation, the OFDM-modulated transmission signal with pilot symbols. FIG. 12 shows an example in which QPSK is used as a modulation method. The interleaving uses random interleaving having a different pattern for each cell. The pilot symbol is an orthogonal code unique to each cell.

  In the present embodiment, the amplitude value calculation unit calculates the amplitude value based on the margin of the amplitude value and the average residual interference power in addition to the number of interference signals to be considered, the number of codewords in one frame, and noise power. The average residual interference power mentioned here corresponds to the average value of the power of the interference signals other than the desired signal and the interference signal to be considered shown in FIG.

  Here, a method of calculating the amplitude value of each code in the amplitude value calculation unit will be described with reference to FIG.

  The number M of interference signals to be considered can be determined, for example, based on the reception power of each user detected in the channel estimation process performed at the time of signal reception. In the example shown in FIG. 13, the number M of interference signals to be considered is obtained by subtracting the number of desired signals (= 1) from the number of signals exceeding a predetermined threshold.

Further, the assumed noise power n ₀ does not fluctuate (ie, is treated as a constant) because it is basically composed of thermal noise.

The average residual interference power is an average value of the power of the interference signal that is not considered, and is used for calculating the amplitude value by increasing the noise variance σ _n ² here.

  Further, the margin of the amplitude value is determined based on the SINR obtained by channel estimation and the error characteristics obtained when decoding the signal. Here, the margin of the amplitude value is adjusted by multiplying the required SNR, that is, ρ, by a constant value.

First, the noise variance σ _n ² is determined in consideration of the average residual interference power (step S21).

  Next, the required SNR, that is, ρ, is determined for margin adjustment of the amplitude value (step S22).

Then, along with the parameter values obtained in the preceding steps S21 and S22, the number of interference signals M to be considered, the number of codewords N in one frame, and the assumed noise power n ₀ are input, and equation (2) is calculated. , And the amplitude value of the code is obtained (step S23).

  It is assumed that the receiver shown in FIG. 16 also corresponds to the transmitter according to the third embodiment shown in FIG.

  For example, the base station as the transmitter according to the present embodiment collects information on the average residual interference power from each terminal, and calculates the amplitude value of each code in consideration of the value. If the average residual interference power is large, the low-level code may be buried in the residual interference and cannot be decoded, so the amplitude of the low-level code is increased. Although the amplitude of the high-level code increases, the number of interference waves to be considered, the number of codes in one frame, the margin of the amplitude value, and the like are adjusted to maintain the average transmission power.

[Supplement]
The present invention has been described in detail with reference to the specific embodiments. However, it is obvious that those skilled in the art can modify or substitute the embodiment without departing from the scope of the present invention. That is, the present invention has been disclosed by way of example, and the contents described in this specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims described at the beginning should be considered.

FIG. 1 is a diagram schematically showing a transmission model according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing a configuration of a receiver according to one embodiment of the present invention. FIG. 3 is a diagram schematically illustrating a configuration of a UCM transmitter according to an embodiment of the present invention. FIG. 4 is a diagram schematically showing a decoding process. Figure 5 is a diagram showing the minimum decodable average _{E rs / (n 0/2} ) for the original code of the required _{E rs / (n 0/2} ) when the number of users and M = 2. Figure 6 is a diagram showing an average _{E rs / (n 0/2} ) when the number of users and M = 3. FIG. 7 is a diagram illustrating a range of the receivable reception power when the code multiplexing number N = 1. FIG. 8 is a diagram showing a range of the receivable reception power when the code multiplexing number N = 2. FIG. 9 is a diagram showing a range of the receivable reception power when the code multiplexing number N = 4. FIG. 10 is a diagram showing a range of the receivable reception power when the code multiplexing number N = 8. FIG. 11 is a diagram illustrating an average bit error rate characteristic when the number of interfering users is one. FIG. 12 is a diagram schematically illustrating a UCM transmitter configuration according to the second embodiment of the present invention. FIG. 13 is a diagram illustrating a process for determining the number of interference signals to be considered. FIG. 14 is a diagram schematically showing a modified example of the transmitter configuration shown in FIG. FIG. 15 is a flowchart illustrating a method of updating the amplitude value when the decoding characteristic is degraded due to an increase in the number of interference signals. FIG. 16 is a diagram schematically illustrating a configuration of a receiver according to an embodiment of the present invention. FIG. 17 is a diagram schematically showing a UCM transmitter configuration according to the third embodiment of the present invention. FIG. 18 is a flowchart for explaining a method of calculating the amplitude value of each code in the amplitude value calculation unit. FIG. 19 is a diagram schematically showing a cell configuration in a mobile radio communication system in which a service area is spread over a plurality of base stations.

Explanation of reference numerals

103, 113, 203 ... encoder X
104, 114, 213 ... encoder Y
107, 205 ... Interleaver A
107, 215: Interleaver B
201, 207: deinterleaver A
202, 208 ... decoder X
211,217 ... Deinterleaver B
212, 218 ... Decoder Y

Claims (33)

A communication system that realizes one-frequency repetition by a non-spreading method and increases capacity,
On the transmitting station side, the transmission information is divided into a plurality of frames, each frame is encoded, each encoded signal is power-amplified with different amplitudes, and the amplified signals are grouped together to perform interleaving over all signals. Send the transmission signal obtained by performing
On the receiving station side, the transmission signal is deinterleaved, sequentially decoded from a code having a large signal-to-interference and noise power ratio, and the decoded signal is re-encoded and sequentially canceled from the transmission signal to restore the original signal. Reproduce the split frame,
A communication system, comprising: Use different interleave patterns for different users,
The communication system according to claim 1, wherein: Use a different interleave pattern for each cell,
The communication system according to claim 1, wherein: On the transmitting station side, change the amplitude amplification ratio for each frame according to the decoding capability on the receiving station side,
The communication system according to claim 1, wherein: On the transmitting station side, determine the number of code multiplexes according to the decoding capability or processing capability realized on the receiving station side,
The communication system according to claim 1, wherein: The transmitting station monitors the state of the propagation path such as traffic at certain intervals. According to the state of the propagation path, the number of interference signals to be considered, the number of codewords per frame, and the power of each code are determined based on the noise power. Update the amplitude value,
The communication system according to claim 1, wherein: On the transmitting station side, when calculating the amplitude value of each code, use the residual interference power consisting of the power sum of the interference waves not considered as an interference wave,
The communication system according to claim 6, wherein: On the transmitting station side, when the average residual interference power is large, the amplitude of the low-level code is increased,
The communication system according to claim 7, wherein: On the transmitting station side, when the amplitude of the low-level code is increased, the number of interference waves to be considered, the number of codes of one frame, and the margin of the amplitude value are adjusted to maintain the average transmission power.
The communication system according to claim 8, wherein: A transmitting device for transmitting information in a non-spreading method,
Frame dividing means for dividing transmission information into a plurality of frames;
Means for encoding each frame;
Power amplification means for power-amplifying each of the encoded signals with different amplitudes,
Interleaving means for grouping the amplified signals and interleaving all the signals;
Transmitting means for transmitting a transmission signal obtained by interleaving,
A transmission device comprising: The power amplifying means changes the amplitude amplification ratio for each frame according to the decoding capability on the receiving station side,
The transmitting device according to claim 10, wherein: The frame division means determines the number of code multiplexing according to the decoding capability or processing capability realized on the receiving station side,
The transmitting device according to claim 10, wherein: Provision is further made for propagation path monitoring means for monitoring propagation path conditions such as traffic at certain intervals,
The power amplifying unit updates the amplitude value of each code based on the number of interference signals to be considered, the number of codewords in one frame, and noise power according to the propagation path condition.
The transmitting device according to claim 10, wherein: The power amplifying means, at the time of calculating the amplitude value of each code, uses a residual interference power consisting of the power sum of the interference waves not considered as an interference wave,
14. The transmitting device according to claim 13, wherein: The power amplifying means, when the average residual interference power is large, increases the amplitude of the low-level code,
The transmitting device according to claim 14, wherein: The power amplifying means, when increasing the amplitude of the low-level code, to maintain the average transmission power by adjusting the number of interference waves to be considered, the number of codes of one frame, and the margin of the amplitude value.
The transmitting device according to claim 15, wherein: A transmission method for transmitting information in a non-spreading method,
A frame division step of dividing transmission information into a plurality of frames;
Encoding each frame;
A power amplification step of power-amplifying each of the encoded signals with different amplitudes,
An interleaving step of grouping the amplified signals together and interleaving all the signals;
A transmitting step of transmitting a transmission signal obtained by interleaving,
A transmission method comprising: In the power amplification step, the amplitude amplification ratio for each frame is changed according to the decoding capability on the receiving station side,
The transmission method according to claim 17, wherein: In the frame dividing step, determine the number of code multiplexing according to the decoding capability or processing capability realized on the receiving station side,
The transmission method according to claim 17, wherein: Further comprising a propagation path monitoring step of monitoring propagation path conditions such as traffic at certain intervals,
In the power amplifying step, the amplitude value of each code is updated based on the number of interference signals to be considered, the number of codewords in one frame, and noise power according to the propagation path condition.
The transmission method according to claim 17, wherein: In the power amplifying step, when calculating the amplitude value of each code, use the residual interference power consisting of the power sum of the interference waves not considered as interference waves,
The transmission method according to claim 20, wherein: In the power amplification step, when the average residual interference power is large, the amplitude of the low-level code is increased,
22. The transmission method according to claim 21, wherein: In the power amplifying step, when the amplitude of the low-level code is increased, the number of interference waves to be considered, the number of codes in one frame, the average transmission power is adjusted by adjusting the margin of the amplitude value.
23. The transmission method according to claim 22, wherein: A transmission signal obtained by encoding each frame obtained by dividing transmission information, power-amplifying the encoded signals with different amplitudes, and combining the amplified signals to perform interleaving over all the signals. A receiving device for receiving
Deinterleaving means for deinterleaving the transmission signal;
Decoding means for decoding sequentially from a code having a large signal-to-interference and noise power ratio,
Signal canceling means for re-encoding the decoded signal and sequentially canceling from the transmission signal;
A receiving device comprising: A transmission signal obtained by encoding each frame obtained by dividing transmission information, power-amplifying the encoded signals with different amplitudes, and combining the amplified signals to perform interleaving over all the signals. A receiving method for receiving
A deinterleaving step of deinterleaving the transmission signal;
A decoding step of decoding sequentially from a code having a large signal-to-interference and noise power ratio;
A signal cancellation step of re-encoding the decoded signal and sequentially canceling from the transmission signal;
A receiving method, comprising: A code multiplexing method for code-multiplexing information transmitted in a non-spreading method,
A frame division step of dividing transmission information into a plurality of frames;
Encoding each frame;
A power amplification step of power-amplifying each of the encoded signals with different amplitudes,
An interleaving step of grouping the amplified signals together and interleaving all the signals;
A code multiplexing method comprising: In the power amplification step, the amplitude amplification ratio for each frame is changed according to the decoding capability on the receiving station side,
27. The code multiplexing method according to claim 26, wherein: In the frame dividing step, determine the number of code multiplexing according to the decoding capability or processing capability realized on the receiving station side,
27. The code multiplexing method according to claim 26, wherein: In the power amplification step, the amplitude value of each code is updated based on the number of interference signals to be considered, the number of codewords in one frame, and the noise power according to the propagation path condition.
27. The code multiplexing method according to claim 26, wherein: In the power amplifying step, when calculating the amplitude value of each code, use the residual interference power consisting of the power sum of the interference waves not considered as interference waves,
The code multiplexing method according to claim 29, wherein: In the power amplification step, when the average residual interference power is large, the amplitude of the low-level code is increased,
31. The code multiplexing method according to claim 30, wherein: In the power amplifying step, when the amplitude of the low-level code is increased, the number of interference waves to be considered, the number of codes in one frame, the average transmission power is adjusted by adjusting the margin of the amplitude value.
The code multiplexing method according to claim 31, wherein: A transmission signal obtained by encoding each frame obtained by dividing transmission information, power-amplifying the encoded signals with different amplitudes, and combining the amplified signals to perform interleaving over all the signals. A decoding method for decoding
A deinterleaving step of deinterleaving the transmission signal;
A decoding step of decoding sequentially from a code having a large signal-to-interference and noise power ratio;
A signal cancellation step of re-encoding the decoded signal and sequentially canceling from the transmission signal;
A decoding method comprising:

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